Production and genetic analysis of resynthesized Brassica napus from a B. rapa landrace from the Qinghai-Tibet Plateau and B. alboglabra

This study aimed to reveal the genetic and epigenetic variations involved in a resynthesized Brassica napus (AACC) generated from a hybridization between a B. rapa (AA) landrace and B. alboglabra (CC). Amplified fragment length polymorphism (AFLP), methylation-sensitive amplified polymorphism, and the cDNA-AFLP technique were performed to detect changes between different generations at the genome, methylation, and transcription levels. We obtained 30 lines of resynthesized B. napus with a mean 1000-seed weight of over 7.50 g. All of the lines were self-compatible, probably because both parents were self-compatible. At the genome level, the S0 generation had the lowest frequency of variations (0.18%) and the S3 generation had the highest (6.07%). The main variation pattern was the elimination of amplified restriction fragments on the CC genome from the S0 to the S4 generations. At the methylation level, we found three loci that exhibited altered methylation patterns on the parental A genome; the variance rate was 1.35%. At the transcription level, we detected 43.77% reverse mutations and 37.56% deletion mutations that mainly occurred on the A and C genomes, respectively, in the S3 generation. Our results highlight the genetic variations that occur during the diploidization of resynthesized B. napus.